Root and tuber crops (RTCs) are the second-most important carbohydrate commodity after cereals. Many species of the RTCs are vegetatively propagated, making their shoot tips the preferred material to be conserved for future uses. Shoot tip cryopreservation provides an important tool to support the long-term conservation of plant genetic resources. Over the past four decades, significant efforts have been undertaken to move shoot tip cryopreservation of RTCs from research projects to full-scale implementation in cryobanks. This comprehensive review focuses on the history of cryopreservation protocols developed in RTCs. The encapsulation and vitrification solution-based cryopreservation techniques followed by ultra-rapid freezing and thawing have been highly successful. Additionally, different strategies for improving the cryotolerance of shoot tips have been introduced to further increase post-cryopreservation recovery. Finally, the research conducted to explain the mechanism underlying cryoprotection and differential cryotolerance including the use of histological studies are highlighted.

In vitro micrografting is an important technique supporting the micropropagation of a range of plant species, particularly woody plant species. Over the past several decades, in vitro micrografting has become a strategy to facilitate shoot recovery and acclimatization of in vitro-grown horticultural species. This review focuses on studies on horticultural crops over the past two decades that cover the establishment of in vitro micrografting, discusses factors affecting the success of in vitro micrografting, and provides commentary on the contribution of micrografting applications to the field of micropropagation. Considering the important roles of micrografting in the restoration of vigor and rooting competence, in promotion of shoot recovery following somatic embryogenesis and organogenesis, and in facilitation of shoot regrowth after cryopreservation, the potential use of this technique in facilitation of genetic engineering and safe conservation of horticultural species are specially highlighted.